Does my data get uploaded anywhere?
No. Everything runs locally in your browser and nothing is sent to a server.
Is this free to use?
Yes. It is completely free, with no account, no signup, and no usage limits.
Does it work on a phone?
Yes. The page runs in any modern mobile browser, on iPhone and Android alike, with no app to install.
Why does my second word start with a lowercase letter?
The upper and lower toggle only advances on letters, and a space does not reset it. If a word ends on an uppercase letter, the first letter of the next word is lowercase. That is the classic mocking-text look, where the alternation runs through the sentence rather than restarting per word.
Can I make it start with a lowercase letter?
Not from the tool, the first letter is always uppercase. Copy the result and change the first character yourself if the lowercase-first look is what you want.
What is alternating case used for?
Almost exclusively for the sarcastic mocking-text meme, where a quoted statement is retyped in alternating capitals to mimic a whining tone. It is also occasionally used as visual noise in a mock-up or as a light obfuscation in casual chat.
Do numbers and punctuation change?
No, they are copied through exactly as typed, and they do not advance the pattern either. A digit in the middle of a word does not interrupt the alternation of the letters around it.
Can I undo it and get my original capitalisation back?
No. The original casing is not stored anywhere, so once the text is alternated, the only way back to a normal sentence is to lowercase it and run the Sentence Case Converter, which will not restore proper nouns.